Some areas in the southern fringes of Edo State are swampy mangrove forests with numerous creeks and rivers dissecting the land area.

In the southwest, there are sandy plains with many rivers and streams. This portion, which is the Benin Lowlands, has a few hills and the land is drained by the lkpoba, Orhionmwon and Osse Rivers.

Going northwards is the Esan Plateau, which is an extension of the plateaux and ranges that are found in the far north areas of the state. They are mainly sandstone plateaux whose heights range from 200 to 300 metres above sea level.

There is a gradual fail into the Orle and Niger Valleys from the north and south, while the landmass in the south and west descends gradually to the Benin Lowlands. The Orle Valley, which runs from the west to east, was formed by a river that cut a ridge in the sandstone sub-strata of the Northern and Esan Plateaux. The area is drained by the Owan and Orle rivers.

The Northern Plateau has ranges that are between 180 and 300 metres of basement rock. Granite peaks are found at random, sometimes rising above 600 metres. The southern portion of this plateau ¡s mainly sandstone.